Route taken: Broadway, Parramatta Rd, Church St, Parramatta to Penrith via Prospect, High St, Henry St, North St, Belmore St, Jane St, then to Emu Plains via Victoria Bridge then Russell St to the M4 Motorway. Then from the end of the M4 Motorway at Governors Drive via Katoomba and Lithgow to Bathurst.

RTA Internal Classification: State Highway No. 5

Proclaimed a State Highway: 7 August 1928

Named: 7 August 1928

The Great Western Highway from Sydney across the Blue Mountains to Bathurst is Australia ’s most historic road. Across it flowed a stream of settlers to the vast areas of the slopers and plains in the western inland. Soldiers, convicts and gold diggers have all trudged and driven along it across the harsh and rocky ridge of the mountain barrier. In the early days of the colony of New South Wales it was probably the construction of this road over the Blue Mountains that saved the small settlement from abandonment.

Since those early days the Highway has remained largely unchanged from its original route, with the exception of a lengthy deviation between Mount Victoria and Bathurst, constructed in the 1830s. Various local deviations have also been constructed to improve the alignment and across much of the Sydney Basin the Highway is no longer the major road, having been superseded by the M4 – Western Motorway.

Today the Great Western Highway begins as the Railway Square intersection in Sydney, then heads west via Broadway, Parramatta Road, Church St, Wentworthville, Prospect, St Mary's to Penrith, where it uses Henry Street, North Street, Belmore St and Jane Street to Castlereagh Road. From Castlereagh Road the Highway thence passes over Victoria Bridge , through Emu Plains and along Russell Street to the M4 – Western Motorway at Leonay. The Highway then recommences at the end of the Western Motorway (at Governors Drive ) and heads to Bathurst via Springwood, Leura, Katoomba, Mt Victoria , Lithgow and Kelso. In Bathurst the Great Western Highway follows Durham and Stewart Streets before terminating at the junction with the Mitchell and Mid Western Highways in Bathurst .

The length of the highway from Harris St, Ultimo, via Broadway, Parramatta Rd, Church St, Prospect, St Mary's, Penrith (via High Street), Emu Plains, Mitchell’s Pass, Springwood, Katoomba, Old Bowenfels, Tarana, Brewongle, Glanmire to the Mitchell and Mid Western Highways in Bathurst was proclaimed State Highway No. 5 on 7 August 1928 . There have been a number of deviations constructed which realigned the highway and they will be discussed further in latter stages of this article. Major re-alignments worth a mention here include between Emu Plains and Blaxland in October 1928 (replaced Mitchell’s Pass), at Penrith in February 1991 (replaced High Street with Henry St, North St, Belmore St, Jane St route) and at Emu Plains in February 2003 where the legal definition of the Great Western Highway was finally modified to incorporate the Western Motorway extension to Lapstone. Also, on 23 January 1993 the Great Western Highway was extended one block east, from Harris Street , Ultimo to Railway Square .

Today the Great Western Highway carries the State Route 31 shield between Harris St, Ultimo and the Hume Hwy (Liverpool Rd) at Summer Hill, the Metroad 4 shield between Wattle St, Haberfield and the Western Motorway at North Strathfield, the State Route 44 shield between North Strathfield and the Western Motorway at Emu Plains and the National Route 32 shield from the end of the Western Motorway at Lapstone to its terminus at Bathurst. The remaining sections of highway are currently unnumbered. It also worth noting that on the Church St , Parramatta Rd and Broadway sections of the Great Western Highway signposting of the local names is preferred.